Valve mechanism for internal combustion engines



Feb. 26, 1935. T. N. SMITH 1,992,721

VALVE MECHANISM FOR INTERNAL COMBUSTION ENGINES Filed FGb. 5, 1933 2Sheets-Sheet l FIGJ. 2.

Feb. 26, 1935. Tl N. Smm-1, 1,992,721

VALVE MECHANISM FOR INTERNAL COMBUSTION ENGINES Filed Feb. 3, 1935 2Sheets-Sheet 2 Patented Feb. 26, 1935 UNITED STATES PATENT OFFICEv VALVEMECHANISM FOR INTERNAL COMBUSTION ENGINES 6 Claims.

This invention relates to internal `combustion engines. Moreparticularly it relates to that type of internal combustion engine shownin Patent No. 1,304,753, Blumberg in which the cylinder head is formedwith a chamber therein into which the intake and exhaust valves open andhaving a main valve controlling communication between the chamber andthe cylinder proper.

It is an object of this invention to provide a motor of this generaltype in which the intake and exhaust valves may be removed through themain valve port.

Another object of the invention is to provide a cylinder head for anengine of this type which may be cast in one piece and still permit theinstallation and removal of the intake and exhaust valves.

Still another object of the invention is to provide a cylinder head inwhich the intake and exhaust valves have their axes inclined to the axisof the cylinder to facilitate their. removal.

Still another object of the invention is to provide an engine in whichthe valves are carried by the cylinder head and each operated by aseparate cam shaft.

Still other and further objects of the invention will hereinafterappear.

In the drawings:

Figure 1 is a front end View of a motor constructed in accordance withthe invention;..

Figure 2 is a sectional view taken on the line 2-2 of Figure 1;

Figure 3 is a sectional view taken on the line 3-3 of Figure 2 with oneof the valve assemblies removed showing the manner in which a valve maybe withdrawn; and

Figure 4 is an inverted plan view of the cylinder head with the valvesand guides removed.

With more particular reference to the drawings, 1 represents onecylinder of a multiple cylinder engine. This cylinder may be providedwith fins 2 in order that it may be air cooled, as shown in the drawingsor may be provided with a suitable water jacket, as is well known in theart. The cylinder 1 is provided with a cylinder head 3 which also may beair cooled by means of fins 4. This cylinder head is preferably cast inone `piece as is shown and is formed with a chamber 5 therein. Thischamber 5 has communication with the cylinder proper through a, pair ofmain ports 6 in the wall between the chamber and the cylinder.

Opening into the chamber from the sides are a pair of intake ports 'land a pair of exhaust ports 8. The roof or upper wallof the chamber 5 ispeaked preferably being formed of two substantially plane surfacesmeeting at an obtuse angle. The intake ports opening into the chamberthrough one of the plane surfaces and the exhaust ports through theother. At the inner ends of the intake and exhaust ports are formed 5valve seats 9 and 10, respectively, which, it will be seen, lie inplanes which are substantially inclined fromthe horizontal. f

'A pair of main valves 11 are mounted for reciprocating movementsubstantially parallel with 10 the axis of the cylinder in the cylinderhead and serve to control communication through the main ports 6 betweenthe chamber 5 and the cylinder. The main valves 11 are preferablymounted in removable valve guides 12 which tightly t into suitableopenings in the cylinder head. Similar valves, such as 13, are providedfor controlling flow through the intake and exhaustl ports 7 and 8.

A pair of intake and a pair of exhaust valves are preferably mounted forreciprocating movement in suitable valve guides such as 14. These valveguides comprise a lower cylindrical portion 15 adapted to fit tightlyinto a suitable opening in the cylinder head and are provided with ashoulder 15a adapted to seat against the upper surface of the cylinderhead and an upwardly extending cylindrical portion 16 adapted to form aguide for the valve stem a substantial distance above the surface of thecylinder head. It is, of course, inherent in poppet valves that the axisof the valve be disposed perpendicular to the plane in which the valveseat lies. As set forth above, the intake and exhaust valve seats 9 and10 lie in planes which are substantially inclined from 35 the horizontaldue to the sloping roof of the chamber 5. It will, therefore, beapparent that the valve stems 13 are inclined a corresponding amountfrom the axis of the cylinder. Preferably the valves are inclinedsufficiently so that their axes lie on lines which extend through themain ports 6. Thus it is possible to machine the valve seats by means ofrotatable tools inserted through the port 6 axially of the valve seat.

The lower cylindrical portions of each of the valve guides are maderelatively thick and are adapted to be withdrawn from the cylinder headwhen it is desired to remove the intake and exhaust valves. Itwill benoted vthat the overall diameter of the intake and exhaust valves isslightly less than the diameter of the ports 6 connecting the cylinderand the chamber. Due to the thickness of the lower cylindrical portion15 of the valve guide it will be seen that when the valve guide iswithdrawn the stem of the valve may be tilted in the opening in thecylinder head sufficiently to clear the edge of the port 6 and permitits removal through this port. This broad principle of removable valveguides which permit the tilting and removal of valves is disclosed indetail in applicants prior Patent No. 1,255,806. The manner in which theintake and exhaust valves may be removed is illustrated by thepositions'of thefvalve 13 as shownin dotted lines at the right hand sideof Figure 3.

In the embodiment shown in the drawings as above described it will benoted that in each cylinder two main valves are shown and also twointake valves and two exhaust valves.- It will be apparent, however,that in general the same advantages and beneficial results will beobtained if a single main valve and a single intake and exhaust valve isprovided for each cylinder. The advantages of the dual valve motor arewell known but it has been found particularly advantageous in a motor ofthis type. The two valves permit a considerable increase in the openingand hence freer and more complete intake and discharge of gases.

The cam means for operating the valve comprises a shaft 17 which ispreferably connected by suitable gearing to the crank shaft of the motorand extends parallel with the front end of the motor. This shaft 17 ispreferably enclosed in a casing 18. The shaft is provided at its upperend with a bevelgear 19 and which meshes with another suitable bevelgear l20 which is secured to the front end of a central cam shaft 21;

Rotatably mounted on yeither side of the main cam shaft 2l are intakeand exhaust cam shafts 22 i which are directly geared through the gears23 i and 24 to the main cam shaft. It will thus be seen that therevolution of the cam operating shaft 17 will cause all three over-headcam shafts to rotate synchronously. Each of the valves 11 and 13 isprovided with a washer 25 secured to the upper end of the valve stem.Confined between this washer 25 and theshoulder 15 of the valve guide isa compression valve spring 26 adapted to hold the valve against itsseat. An inverted cup or piston 27 is placed over the upper end of thevalve stem and washerv to provide a surface on which the cam mayoperate. Each pair of valves is enclosed by a casing such as 28 whichsurrounds the portion of the valve stem which extends above the cylinder`head and serves as an additional guide for the valves. y

The cam shafts 21 and 22 are provided with suitablecams 30 which operateon the upper surfaces of the inverted cups 27 and cause reciprocation ofthe valves. These c ams are so arranged that they will cause the mainvalves 1v1 to open simultaneously with the exhaust valves and remainopen while the burnt gases from the cylinder are discharged into Athechamber 5 and out through the exhaust port. The exhaust valves will thenclose and the main valves 11 will continue to remain open while theintake valve opens and a fresh charge is'drawn into the cylinder. Theintake valves and the main valves are then closed simultaneously.

It will, therefore, be seen that the exhaust valves are not constantlyexposed to the heat of the explosion and the passage of the hot gasesfrom the cylinders. The main valves 11 although exposed to eachexplosion within the cylinder will be in some measure cooled by thepassage of the incoming cool gases of the intake charge and willtherefore be alternately heated and cooled. It is an object of thisinvention to provide a motor in which the valves may be kept as cool aspossible and thus add materially to their life.

Engines having valve arrangements somewhat similar to the above havelong been known in the prior art as evidenced by the patent to Blumbergabove referred to. However, the defects and difficulties of theinventions shown in the prior art are numerous. In the present inventionit is seen that it is possible to casta cylinder.y head for this type ofmotor in a single one piece casting and yet permit the machining of thevalve seats within the chamber in the cylinder head and also permit theeasy removal of the intake and exhaust valves. It will be seen that theintake and exhaustv valves may be removed by withdrawing the Valveguides 14 and tilting the valve stems sufciently to permit the valves topass through the main ports 6. This is possible due to the fact that the.intake and exhaust valves are inclined at an angle to the axis of thelcylinder and to the axis of the main valve. Inasmuch as to permit this,it is necessary to provide inclined intake and exhaustv valves, it hasbeen necessary also to provide independent cam shafts for each set ofvalves in order to effect eflicient operation of the motor. In enginesof this general type it is customary to provide lateral intake andexhaust ports and hence the inclination of the intake and exhaust valvespermits a substantial straightening out in the passage ways from thecylinder through the ports. Also, the inclination of the valves andtheir seating on the inclined roof of the chamber in the cylinderheadpermits a maximum effective opening of the valves in a minimumamount of space due to the fact that relatively larger valves may beemployed. Many and various modifications of the invention are obviousfrom the foregoing only one of which has been illustrated in thedrawings.

`What Iclaim is:

1. In an internal combustion engine, a cylinder, a cylinder head, achamber in said cylinder head, a main port connecting said chamber andsaid cylinder, a main valve for controlling communication between saidchamber and said cylinder, intake and exhaust ports communicating withsaid chamber, reciprocating intake and exhaust valves controlling saidintake and `exhaust ports and means permitting the removal-of saidvalves through said main ports.

2. 'In an internal combustion engine, a cylinder, a cylinder head, achamber in said cylinder head, a main port connecting said kchamber andsaid cylinder, a main valve for controlling communication betweensaidchamber and said cylinder, intake and exhaust ports communicatingwith said chamber, reciprocating intake and exhaust valves` controlling`said ports, removable valve guides tted in said cylinder head and whenremoved permitting tilting of the' valves whereby they may be removedthrough said main port.

3. In an internal combustion engine, a cylinder, a cylinder head, achamber in said cylinder head,

a main port connecting said chamber and said a main port connecting saidchamber and said cylinder, a main valve controlling communicationbetween said chamber and said cylinder, intake and exhaust portscommunicating Vwith said chamber, intake and exhaust valves, having axesinclined to the axis of the cylinder for controlling said intake andexhaust ports and relatively long removable guides for the stems of saidvalves, whereby when a guide is removed the valve may betilted laterallyto permit its removal through said main port.

5. In an internal combustion engine, a cylinder, a one piece cylinderhead having a chamber therein, a port connecting said chamber and saidcylinder, a main valve for controlling said port intake and exhaustports communicating with said chamber and intake and exhaust valves forcontrolling said ports, said intake and exhaust valves having their axesinclined to the axis of the cylinder and means permitting the removal ofsaid valves through said main port.

6. An internal combustion engine having a cylinder, a cylinder head, achamber within said cylinder head, a main port connecting saidchamberand cylinder, a main valve for controlling said main port, intake andexhaust ports communicating with said chamber, intake and exhaust valvesfor controlling said intake and exhaust ports, the axes of said intakeand exhaust valves being in clined to the axis of the cylinder andextending moved therethrough.

THOMAS NOAH SMITH.

